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Re: Going the distance

Les and Ed:

We might be able to estimate the potential size of the 5 to 10 km application
segment by looking at shipments of LX ports today if the transceiver vendors
have the data and are willing to share it.

But more important than the mix of LX to SX ports  is the fact that many
customers today  have a requirement to go these kind of distances. The number of
LX ports sold might be small compared to SX but this kind of application is
pulling a lot of GbE business.  If you want me to quantify it, I'd say of the
last ten customers I have been in meetings with, 3 of them were looking to use
the 10 km LX solution to go 5 to 10 km.

Also I am not all that comfortable with the unstated assumption in much of the
previous debate that the short distances are in fact the major market for 10
GbE.  The logical application for 10GbE in the LAN and Campus is to aggregate
lots of GbE segments, which means between buildings and between rather large
capacity switches that could be a long way apart (shall we call it a MAN?).

Bruce Tolley
3Com Corporation

Les Poltrack <lap@xxxxxxxxx> on 06/30/99 12:54:03 PM

Sent by:  Les Poltrack <lap@xxxxxxxxx>

To:   Ed Grivna <elg@xxxxxxxxxxx>, rtaborek@xxxxxxxxxxxxxxxx, Bruce
cc:   hfrazier@xxxxxxxxx, stds-802-3-hssg@xxxxxxxx
Subject:  Re: Going the distance

Ed, you raise a good point and I wish I could answer with an
absolute percentage on the requirement.

There was another point raised that this might be more of a
marketing question than anything else.  For what it's worth,
my subjective marketing perspective, based on talking to
hundreds of users about Gigabit Ethernet and their expectations
for Ethernet backbone technologies, is that Bruce Tolley's
suggestion of 5 to 10 km is right on the mark.

I don't have the incontrovertible quantitative data I'd like to
have on the distribution of distances required, but I would say
that a good point was raised earlier that the fact that most
long wavelength Gigabit Ethernet devices support 10km has
created somewhat of an expectation for backbone distances
in customer's mind and support of 10km by 10 Gigabit Ethernet
devices would materially enhance the adoption of the technology.

My two cents is that 10km is the right goal for a volume singlemode
high speed backbone technology.


Les Poltrack
Cisco Systems, Inc.

At 11:35 AM 6/30/99 -0500, Ed Grivna wrote:
>Bruce, while I do not dispute your facts, I do question your
>conclusion.  Just because some small part of the populace is doing
>something does not necessarily require that it be standarized.
>As is evident by the statement itself, for those small segments of
>the market that have needs beyond those that are standardized, there
>are often low-cost avenues that they can persue to fill those needs.
>The fact that they are using LX beyond the rated distances even
>puts into question if what they have is really a 1000Base-LX link.
>It may well be constructed with LX compatible components and be
>running the proper protocols, but that doesn't necessarily make it
>an LX link.
>The requirements for the standards committee are to standarized those
>areas of the technology where such effort would benefit the overall
>user community, not 1 or 2 users or potential users.  Unless this
>market segment can be quantified into a reasonable percentage of
>the overall market, I question whether a standarization effort is
>Are we talking 5%, 1%, 0.1%, or 0.001% of the market?   At some point
>it is necessary to make a cut, and state that the user may create links
>beyond these bounds, but that their implementation is beyond the scope
>of the standard.
>-Ed Grivna
>Bruce Tolley wrote:
>> The point has been made before that today customers are already going
>> 5 to 10 Km with 1000BASE-LX.  There should be no debate that it is a
>> market requirement to go 5 to 10 km with 10 GbE.
>> While I am willing to consider accepting  a conservative 2 to 3 km
>> goal as the official goal of the project,  we need to acknowledge
>> that this is a conservative goal and, as we get on with the work
>> of the project , we should investigate whether we can stretch this goal..
>> Bruce Tolley
>> 3Com Corporation
>> Rich Taborek <rtaborek@xxxxxxxxxxxxxxxx> on 06/29/99 05:01:32 PM
>> Please respond to rtaborek@xxxxxxxxxxxxxxxx
>> Sent by:  Rich Taborek <rtaborek@xxxxxxxxxxxxxxxx>
>> To:   Howard Frazier <hfrazier@xxxxxxxxx>, HSSG <stds-802-3-hssg@xxxxxxxx>
>> cc:    (Bruce Tolley/HQ/3Com)
>> Subject:  Re: Going the distance
>> Howard,
>> I will gladly accept your suggestion of removing the portion of the
>> motion in parenthesis as a  friendly amendment post-haste given your
>> support of this motion as a seconder.
>> - Rich
>> Howard Frazier wrote:
>> > The more I think about it, the more I like the idea of adopting the
>> > 802.3z link distance objectives for 10 Gig. We should remember that
>> > we are still in the study group phase, trying to scope out a project.
>> > We can always adjust the objectives later.
>> >
>> > Let me therefore state my support for Rich's proposed motion:
>> >
>> > > "Support the premises cabling plant distances as specified in
>> > > ISO/IEC 11801"
>> > >
>> > > The distances supported in ISO/IEC 11801 are:
>> > >
>> > > 100 m for horizontal cabling (applicable to copper, MMF, SMF)
>> > >
>> > > 550 m for vertical cabling: (applicable to SMF and possibly MMF)
>> > >
>> > > 2-3 km for campus cabling: (applicable to SMF)
>> >
>> > Rich, I would encourage you to drop the parenthesis.
>> >
>> > If we adopt this objective, we can make progress on the rest of the
>> > work we need to do as a study group.  As was demonstrated in 802.3z,
>> > we will need to review the objectives periodically, and revise them
>> > if there is consensus to do so.
>> >
>> > Howard Frazier
>> > Cisco Sytems, Inc.
>> -------------------------------------------------------------
>> Richard Taborek Sr.    Tel: 650 210 8800 x101 or 408 370 9233
>> Principal Architect         Fax: 650 940 1898 or 408 374 3645
>> Transcendata, Inc.           Email: rtaborek@xxxxxxxxxxxxxxxx
>> 1029 Corporation Way    
>> Palo Alto, CA 94303-4305    Alt email: rtaborek@xxxxxxxxxxxxx